Category Archives: CNC

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As part of my effort to reduce the noise and vibration in the Y axis, I am going to try using a screw drive instead of the 5mm pitch belt. I rescued a screw drive assembly from a big XY table but it uses a 200W servomotor for which I have neither power supply nor drive electronics. Never fear! The motor was a NEMA-34 size, so I designed an adapter to mount the NEMA-23 stepper that MegaMax uses in the NEMA-34 motor mount. Next I needed a shaft coupler- the screw has a 9mm diameter attachment and the NEMA-23 motor has a 1/4″ shaft.

Adapter plate on NEMA-23 motor

I used DesignSpark Mechanical to design the motor mount adapter and flexible shaft coupler. I uploaded the motor adapter to Thingiverse (http://www.thingiverse.com/thing:526424) and it proved surprisingly popular so I designed another that adapts a NEMA-23 mount for a NEMA-17 motor (http://www.thingiverse.com/thing:526443). I had to make two attempts at the flexible shaft coupler- the first design proved a little too springy and flexible, so I tried again with a more beefy design. It turns out it is pretty easy to design this sort of thing in DSM. I probably spent 30 minutes on the first one and about 10 minutes on the second one.

I sliced in Cura because Slic3r was having some problems. The prints look a little rough because of all the support material required to print the springs, but they work fine.

A few weeks ago Mike Stone of CNCMogul.com visited the Milwaukee Makerspace.

Mike donated one of his machines to the space for testing and feedback as well as to use for the membership. It should also be mentioned that Mike is local and has his shop and distribution in Wales, Wisconsin.

Joe Rodriguez built one machine and I also put one together at our shop at home. So here are some thoughts on the process as well as some pictures. It isn’t a review as these machines haven’t really been put to the test as of yet. Time will tell.

The CNC Mogul is a general purpose 3 axis CNC kit that is relatively easy to put together and can be used for anything that you like. I’ll be using ours for routing and Joe wants to make a CNC plasma cutter with the one in the space. The basic kit is affordable and it uses the Makerslide as it’s building blocks. The stepper motors are run with a rack and pinion setup on aluminum tracks and gearing as well.

The controller is a Chinese Tb6560 Stepper Motor Driver Controller that is controlled via parallel port.

The power supply is a 24V 14.6 AMP 350W Max Power Supply.

The whole kit can be ordered online from 2ft X 3ft up to 4ft X 8ft. Custom dimensions are also available.

So here is the kit before assembly. This is a 3ft x 3ft kit that I will be building and using with a router.

This is the kit right before opening.

Inside the kit there are a bunch of baggies with tons of little parts. You can look at the manual here

I’m assembling the quad rail kit. Once I start pulling things out of the box there is an amazing array of parts that explodes out of it. Fortunately each bag and part are well marked.

Everything that you need to build your own CNC controlled machine.

Everything is labeled really well.

Everything is labeled really well.

The kit took approximately 3+ hours to put together. The documentation in the manual is hit or miss. The pictures are extremely good and really help in putting this together. The accompanying text is also great for the first 1/3 of the manual and then you’re left to interpret pictures from there. There are a few questions that came up while building this but fortunately I was able to figure it out.

Little by little the parts are being built.

After the gantry gets built and all of the wires are connected it’s time to test. CNC Mogul recommends using Mach 3 for your machine control. And even has a few pointers on how to setup Mach 3 on their site.

I decided to go with LinuxCNC because it’s open source, I’m comfortable with Linux and it’s low cost (free). I loaded it up on a spare computer and after running through the instructions I was able to control the stepper motors on the Mogul.

What I had difficulty with is that the CNC Mogul uses an “A” axis and “Y” axis slaved together. LinuxCNC can do that but you can NOT test for that in the setting up process. You essentially tell the “A” axis to use the same step and direction pulses as the “Y” axis. I also inverted the “A” axis so they would turn the same direction when they are facing each other.

One of the other difficulties I had was figuring out the leadscrew pitch to enter into LinuxCNC. After some experimentation 1.27 inches per revolution seems about right but some more testing is needed.

Once you’re finished building the whole thing you need to mount it to something. I picked up a Craigslist find and the Mogul fit perfectly.

Silversark put together an amazing fashion show on Friday to showcase pieces she made inspired by church architecture and her trip to the Netherlands. This is something I cooked up for a background piece for the show.

The design work took several months and the actual creation of the piece took about a week, working 12-16 hours a day. The frame is made from CNC routed aspen (thanks, Jason H.!) which is a rather “fuzzy” wood and required two days to hand finish, including the use of a set of needles files to smooth out the inset edges.

The acrylic panels were hand-stained with Gallery Glass stain and simulated liquid leading. They’re not quite finished yet, but I plan to complete the staining within the next week.

Recently, I’ve been doing some work sandblasting. Because Pi Day was coming up (March 14 – 3.14), and I just happened to have a stack of Pyrex pie pans handy, I thought I’d go ahead and try making my own custom Pi Pans.

I started by designing a logo in Illustrator. Well, that’s not quite right. I actually did an image search for “Pi”, saved a .bmp, and then TRACED it in Illustrator. Once in vector format, the image can be re-sized and have the stroke and fill colors changed, all non-destructively. When I was happy with the logo, I printed one out on plain paper. Then, I cut it out and taped it to the back of a pie pan. This gave me a real-world mock-up to make sure I liked what I had BEFORE going through the trouble of making a vinyl stencil and sandblasting.

Next, I exported my image as a .DXF file, and then opened it in Silhouette Studio, the software that runs the CNC vinyl cutter machine. In studio, I made sure the image was still scaled correctly, then positioned it where I wanted it on the 12″x12″ cutting area. The last thing I did before cutting was to FLIP the image. Since I would be sandblasting on the BACK of a glass pie pan, the image needs to be flipped so it is viewed correctly from the front.

The Silhouette Cameo cutter cuts out the pattern quickly and automatically, taking about a minute for the whole process.

I removed the vinyl, and cut it into quarters, as I was able to fit four stencils on a single page. I then peeled away the “Pi” logo, leaving the vinyl around it. This is because I am making a stencil. I want the sandblaster to hit the glass where the vinyl does NOT protect it. This will etch the shape of Pi and leave the glass around it clear.

I used transfer tape to place the Pi logo stencil on the back of the pie pan, and then removed the transfer tape. Next, I covered the rest of the back of the glass with regular masking tape. At this point, the pie pan is ready for sandblasting.

I put the pan into the blast cabinet and set the pressure regulator to about 70 PSI. Anywhere from 60-80 works pretty well. Higher pressure than that can start to cut into the vinyl. I simply held the pie pan in one hand and pointed the sandblaster gun at it with the other. It’s much like spray painting – just pull the trigger and try to give a nice even coat.

Once done sandblasting, I pulled the pan out of the cabinet and peeled away all the masking. Next, I washed it with soap and water in the utility tub and then dried it.

The finished effect turned out pretty well. The Pi is a very prominent white frosted character on a clear background. Most people catch the visual pun of “Pi Plate” right away.

Besides the Pi Plate, I also came up with “Apple Pi” and “Raspberry Pi” designs based on popular computer company logos. Both of those turned out very well.

By that time, I was starting to feel pretty confident in my stencil design and sandblasting skills, and I wanted to make a “Cherry Pi” logo, but realized that there is already a great pattern for that – the album art from Warrant’s 1990 album “Cherry Pie”.

I spend some time in the vector software painstakingly tracing the artwork into a simplified vector. Next, I made a cutting from vinyl. All of the fine lines were tricky to peel off with a pair of Xacto knives. Once I finally had the finished stencil applied to another pie pan, it was time to sandblast.

After that, I simply peeled off the masking to reveal my WARRANT CHERRY PIE pan. My wife’s birthday happens to be March 14th – Pi Day. She’s a fan of late 80’s/early 90’s rock, so gave her the CHERRY PIE pan (with a home-baked cherry pie in it) as a Pi Day/Birthday gift. She got a kick out of it.

How about you? Have you ever personalized some glassware through etching? A “Please return this pan to….” etching sounds like a good idea for pot-lucks! If you have done some etching, post a photo or link! Otherwise, send your ideas for other cool glass etching on up cycled kitchen-ware!

With a lot of hard work from Ed H. and Steve P. our 4′ x 8′ CNC router has achieved a milestone, instead of the X axis sitting on the ground it has taken a leap up and is now mounted, ready for the Y and Z axis to be mounted to it along with the electronics and motion control.

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